I. Technical Field
This invention pertains to telecommunications, and particularly to the upgrade (e.g., update or replacement) of software at nodes of a radio access network (RAN).
II. Related Art and Other Considerations
In a typical cellular radio system, mobile terminals (also known as mobile stations and mobile user equipment units (UEs)) communicate via a radio access network (RAN) to one or more core networks. The user equipment units (UEs) can be mobile stations such as mobile telephones (“cellular” telephones) and laptops with mobile termination, and thus can be, for example, portable, pocket, hand-held, computer-included, or car-mounted mobile devices which communicate voice and/or data with radio access network.
The radio access network (RAN) covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a radio base station (RBS), which in some networks is also called “NodeB” or “B node”. A cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site. Each cell is identified by a unique identity within the local radio area, which is broadcast in the cell. The base stations communicate over the air interface (e.g., radio frequencies) with the user equipment units (UE) within range of the base stations. In the radio access network, several base stations are typically connected (e.g., by landlines or microwave) to a radio network controller (RNC). The radio network controller, also sometimes termed a base station controller (BSC), supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks.
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile communication system, which evolved from the Global System for Mobile Communications (GSM), and is intended to provide improved mobile communication services based on Wideband Code Division Multiple Access (WCDMA) access technology. UTRAN is essentially a radio access network providing wideband code division multiple access for user equipment units (UEs). The Third Generation Partnership Project (3GPP) has undertaken to evolve further the UTRAN and GSM based radio access network technologies.
In a case such as WCDMA networks, as many as a few hundred radio base station nodes may be connected to an RNC. In WCDMA, a radio network controller (RNC) and its subservient radio base stations are collectively known as a Radio Network System (RNS). Similarly, in GSM the radio base stations (typically called “base transceiver stations” or “BTS” in GSM) are connect to a base station controller (BSC) node, with a BSC and its subservient base transceiver stations being collectively referred to as a Base Station Subsystem (BSS).
The radio networks of established operators now have radio base stations (RBS) numbering in the thousand deployed across their networks. When an operator/vendor releases a software revision (e.g., a software release) for the radio base station nodes of its network, all the radio base stations of the operator's network must undergo software update (e.g., software upgrade). The software updates typically require that a radio base station will be out of service for the duration of the update. Generally a radio base station can only be taken out of service during fixed or time-established maintenance windows.
Typically a radio base station is updated through the use of an Operational Support System (OSS). Through its Operational Support System (OSS) the operator typically selects the nodes to be update from a list and initiates the upgrade of those nodes.
Given the size and scale of a typical network, a single Operational Support System (OSS) generally cannot typically handle a full network upgrade within a single maintenance window. This is because, e.g., (i) there are too many radio base stations for the Operational Support System (OSS) to upgrade the whole network in parallel; and (ii) the upgrade duration means that only a limited number of groups can be handled in the maintenance time window.
Rather than upgrading the whole network in parallel, the software upgrades for the radio base station nodes are typically implemented by groups of radio base stations. Group by group implementation of software revisions of the many constituent radio base station nodes of a network, e.g., during maintenance windows, can take an inordinately long time, e.g., weeks in some instances. In cases of WCDMA networks having radio network controller (RNC) nodes, for example, the upgrade can be logically broken down according to the radio network systems (RNS), e.g. radio network systems (RNS) are upgraded at different times. Similarly, in GSM the upgrade can be implemented at different times for different base station systems (BSS).
Even when the software for upgrade radio base stations is upgraded in groups, the software upgrade involves interaction of the Operational Support System (OSS) with each radio base station. FIG. 1 shows, for example, by solid arrows an Operational Support Entity (OSE) downloading a software upgrade for plural radio base stations of a network. FIG. 1 further shows, by broken lines, each radio base station of the network reporting the progress/status of its software upgrade to the Operational Support Entity (OSE).
Long Term Evolution (LTE) is a variant of a 3GPP radio access technology wherein the radio base station nodes are connected directly to a core network rather than to radio network controller (RNC) nodes. In LTE, in general functions of a radio network controller (RNC) node are performed by the radio base stations nodes. As such, the radio access network (RAN) of an LTE system has an essentially “flat” architecture comprising radio base station nodes without reporting to radio network controller (RNC) nodes. The flat architecture of the LTE network makes the software upgrade activity more challenging and labor intensive since, e.g., there are no obvious groupings for software upgrade.
When a software upgrade is unsuccessful at a node, the upgrade is “rolled back” to an original (e.g., previous) software package in order to ensure consistent operation of that region or the radio network controller (RNC). Thus, even if a radio base station grouping were established for sake of software upgrade in an LTE network, it would be unclear (in the case of an upgrade being unsuccessful) which other radio base stations in the group or network should also be rolled back to the original software package.